1. Field of the Invention
The invention relates to a process of producing plural light emitting panels by sealing plural luminous regions between a support substrate and a seal plate which constitute a unit and by dividing the resulting product.
Also, the invention relates to a process of producing plural display panels by sealing plural display regions between a support substrate and a seal plate which constitute a unit and by dividing the resulting product.
Also, the present invention relates to a display panel.
2. Description of the Related Art
A remarkable attention has been focused on electroluminescence (hereinafter abbreviated as an organic EL) elements as self-emitting type luminous elements in recent years and organic EL displays using these organic EL elements are being developed. Organic EL elements have the characteristics, such as high response speed and operations carried out under low voltage by low power consumption, which are preferable for displaying moving images and therefore, these organic displays are expected to become displays in the next generation including portable telephones and personal digital assistants (PDA) of the next age.
These organic EL displays are provided with an organic EL display panel having a display region containing plural organic EL elements for image display, a driving circuit and a driving power source.
The organic EL element is deteriorated in luminous characteristics when it is in contact with moisture and it is therefore necessary to make an organic EL display panel by sealing the organic element such that the organic EL element is not brought into contact with moisture. The organic EL display panel is produced by applying a seal plate, through an adhesive, to a support substrate on which organic EL elements are formed.
In a process of producing the organic EL display panel, a production method called multiple image production is frequently adopted. The multiple image production is a method in which a specified number of display regions composed of an organic EL element are formed simultaneously on one large support substrate having a size specified times that of one organic EL display panel, one large seal plate having the same size as the support substrate is applied to the display region side of the support substrate by using an adhesive and a laminate of both plates applied to each other is divided into plane pieces each including one display region. This method makes it possible to produce a specified number of organic EL display panels each having the above display region simultaneously.
As one of methods of producing an organic EL display panel in the above production method, there is a method in which a support substrate and a seal plate are sealed through a photocurable resin, the photocurable resin except for dividing parts is selectively cured and the substrate is divided at parts where an uncured photocurable resin is left into pieces containing each EL display panel (see the publication of Japanese Patent Application Laid-Open No. 2001-126866).
However, in order to selectively cure the part covering the above display region among the photocurable resin as mentioned above in the method of producing an organic EL display panel which method is described in the publication of Japanese Patent Application Laid-Open No. 2001-126866, it is necessary to use an exposure mask in which a light-shading part is formed so as to prevent the dividing parts from being irradiated with light and to irradiate the photocurable resin with light through the transmitting part of the exposure mask after this exposure mask is subjected to alignment. Therefore, there is such an disadvantage that the steps of producing the organic EL display panel are increased.
Moreover, there is the disadvantage that an uncured photocurable resin adheres to the organic EL display panel when the above display regions are divided. There is the possibility that such an uncured photocurable resin adheres to various places in the subsequent working steps and therefore, the uncured photocurable resin is removed by washing. As a washing method, there is a method in which the uncured photocurable resin is wiped using an organic solvent such as alcohol and a method in which the organic EL display panel is dipped in an organic solvent. However, in this case, the organic solvent and the like penetrate into the organic EL display panel during washing and there is therefore a fear that the luminous characteristics and reliability of the organic EL element are lowered by, for example, a deterioration in the organic material present in the above display region. Also, such a washing operation must be carried out every individual organic EL display panel after the above display regions are divided, and therefore, the yield of production is dropped because the steps of producing the organic EL display panel are increased.
As mentioned above, according to the method of producing an organic EL display panel described in the publication of Japanese Patent Application Laid-Open No. 2001-126866, the drop in the yield of production causes high production costs.